The present invention relates to control of power supply to a glow plug.
Glow plugs are used to aid ignition in diesel engines. There is conventionally known an energization control apparatus for a glow plug, which includes a semiconductor switching element to turn on and off energization of the glow plug. This type of glow plug energization control apparatus is sometimes provided with a temperature fuse so as to suppress abnormal overheating in the event of a failure in the semiconductor switching element. For example, Japanese Unexamined Patent Publication (Translation of PCT Application) No. 2008-530727 (hereinafter abbreviated as “Patent Document 1”) discloses a glow plug energization control apparatus provided with a semiconductor switching element and a temperature fuse in which, when the semiconductor switching element reaches a high temperature upon the occurrence of a failure, the temperature fuse becomes disconnected by the action of a spring element. Japanese Unexamined Patent Publication No. 2012-172568 (hereinafter abbreviated as “Patent Document 2”) discloses a glow plug energization control apparatus provided with a semiconductor switching element, a temperature fuse and a reverse connection protection FET (field effect transistor) in which, upon detection of a failure in the semiconductor switching element, the reverse connection protection FET causes heat generation by the passage of electric current through a parasitic diode of the reverse connection protection FET so as to disconnect the temperature fuse.